I can't believe that even while basing their "OS" on basic Debian they can't to what every other home cooker can do, make a regular installable OS, and on top of that it requires UEFI... The OS that's supposed to let you build your own steam boxes or use existing computers to stream from a powerful gaming computer somewhere else...
Quality... I've seen 12 year old home cookers do better. Heck the guy making his fantasy Linux distro on this forum before he got predictably tired of it did better.
HawkMan - the UEFI issue can be worked around - depending on how you want to do the evaluation process. (Both Oracle VirtualBox and vmWare have EFI support; there's a post in the SteamOS SteamCommunity forums on how to create a bootable ISO for vmWare in EFI mode - it also works for Oracle VB, vmWare Player 5, or vmWare Workstation 10; that is something I have tested personally.)
Still, I think the UEFI "requirement" is simply a screen-out factor - it eliminates older hardware (basically, anything older than LGA1366 or the AMD equivalent) from consideration by OEMs.
Here are the settings I used for vmWare Workstation 10:
Guest RAM: 1536K (I have 4096K total on the host - this setting is just under half the total RAM available, and leaves room for running other software on the host while the VM is running.)
Guest HDD: 32 GB (This figure is actually high for vmWare Debian guests - vmWare recommends less than a quarter of this figure. SteamOS did NOT use it all.)
Guest OS setting: Debian 7 (64-bit) (Directly from the SteamOS FAQ.)
Other than enabling EFI support in the VM via an edit (vmWare requires it, in Oracle VB, it's a switch in the VM settings), the same settings work in Oracle VB. (Naturally, you can, and likely should, increase the amount of RAM if you can, as my own settings are less than half what Valve specifies - however, it will still work, despite being under-spec.)